diff --git a/NAMESPACE b/NAMESPACE
index e2a2f8d..b111ecf 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -6,6 +6,7 @@ S3method(author_with,cranly_network)
 S3method(build_dependence_tree,cranly_network)
 S3method(build_network,cranly_db)
 S3method(depends,cranly_network)
+S3method(enhances,cranly_network)
 S3method(imports,cranly_network)
 S3method(linking_to,cranly_network)
 S3method(package_by,cranly_network)
@@ -26,6 +27,7 @@ export(clean_up_author)
 export(clean_up_directives)
 export(compute_dependence_tree)
 export(depends)
+export(enhances)
 export(imports)
 export(linking_to)
 export(package_by)
diff --git a/R/cranly-package.R b/R/cranly-package.R
index 6c5f815..7c4a203 100644
--- a/R/cranly-package.R
+++ b/R/cranly-package.R
@@ -131,6 +131,11 @@ linking_to <- function(x, package = NULL, exact = FALSE) {
     UseMethod("linking_to")
 }
 
+#' @rdname package_by
+#' @export
+enhances <- function(x, package = NULL, exact = FALSE) {
+    UseMethod("enhances")
+}
 
 
 #' \code{build_network} method for an object
diff --git a/R/extractors.R b/R/extractors.R
index d38aa8a..c98fddc 100644
--- a/R/extractors.R
+++ b/R/extractors.R
@@ -9,7 +9,7 @@ package_by.cranly_network <- function(x, author = NULL, exact = FALSE) {
     if (any(is.infinite(author))) {
         return(unique(unlist(x$nodes$package)))
     }
-    perspective <- attr(x, "perspective")
+
     if (exact) {
         str <- paste(author, collapse = "$|^")
         str <- paste0("^", str, "$")
@@ -24,7 +24,7 @@ package_by.cranly_network <- function(x, author = NULL, exact = FALSE) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 
 }
@@ -38,7 +38,7 @@ package_with.cranly_network <- function(x, name = NULL, exact = FALSE) {
     if (any(is.infinite(name))) {
         return(unique(unlist(x$nodes$package)))
     }
-    perspective <- attr(x, "perspective")
+
     ## Escape .
     name <- gsub("\\.", "\\\\.", name)
     if (exact) {
@@ -49,14 +49,15 @@ package_with.cranly_network <- function(x, name = NULL, exact = FALSE) {
         str <- paste(name, collapse = "|")
     }
     package <- unlist(x$nodes$package)
-    inds <- grep(str, package, ignore.case = !exact, perl = TRUE)
+
+    inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
     out <- unique(package[inds])
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 
 }
@@ -70,7 +71,7 @@ author_of.cranly_network <- function(x, package = NULL, exact = FALSE) {
     if (any(is.infinite(package))) {
         return(unique(unlist(x$nodes$author)))
     }
-    perspective <- attr(x, "perspective")
+
     package <- gsub("\\.", "\\\\.", package)
     if (exact) {
         str <- paste(package, collapse = "$(?!\\.)|^")
@@ -79,14 +80,15 @@ author_of.cranly_network <- function(x, package = NULL, exact = FALSE) {
     else {
         str <- paste(package, collapse = "|")
     }
-    inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
+
+    inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
     out <- unique(unlist(x$nodes[inds, "author"]))
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 }
 
@@ -99,7 +101,7 @@ author_with.cranly_network <- function(x, name = NULL, exact = FALSE) {
     if (any(is.infinite(name))) {
         return(unique(unlist(x$nodes$author)))
     }
-    perspective <- attr(x, "perspective")
+
     if (exact) {
         str <- paste(name, collapse = "$|^")
         str <- paste0("^", str, "$")
@@ -108,27 +110,31 @@ author_with.cranly_network <- function(x, name = NULL, exact = FALSE) {
         str <- paste(name, collapse = "|")
     }
     authors <- unlist(x$nodes$author)
-    inds <- grep(str, authors, ignore.case = !exact)
+    inds <- sapply(x$nodes$author, function(z) any(grepl(str, z, ignore.case = !exact)))
     out <- unique(authors[inds])
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 }
 
 #' @rdname package_by
 #' @export
 suggests.cranly_network <- function(x, package = NULL, exact = FALSE) {
+    if (attr(x, "perspective") == "author") {
+        stop(match.call()[[1]], " is not designed for cranly_network objects with perspective = 'author'")
+    }
+
     if (is.null(package)) {
         return(NULL) # return(unlist(x$nodes$Package))
     }
     if (any(is.infinite(package))) {
         return(unique(unlist(x$nodes$suggests)))
     }
-    perspective <- attr(x, "perspective")
+
     package <- gsub("\\.", "\\\\.", package)
     if (exact) {
         str <- paste(package, collapse = "$(?!\\.)|^")
@@ -137,15 +143,16 @@ suggests.cranly_network <- function(x, package = NULL, exact = FALSE) {
     else {
         str <- paste(package, collapse = "|")
     }
+
     inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
-    ## inds <- sapply(x$nodes$Package, function(x) any(grepl(str, x)))
+    ## inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
     out <- unique(unlist(x$nodes[inds, "suggests"]))
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 }
 
@@ -153,13 +160,17 @@ suggests.cranly_network <- function(x, package = NULL, exact = FALSE) {
 #' @rdname package_by
 #' @export
 imports.cranly_network <- function(x, package = NULL, exact = FALSE) {
+    if (attr(x, "perspective") == "author") {
+        stop(match.call()[[1]], " is not designed for cranly_network objects with perspective = 'author'")
+    }
+
     if (is.null(package)) {
         return(NULL) # return(unlist(x$nodes$Package))
     }
     if (any(is.infinite(package))) {
         return(unique(unlist(x$nodes$imports)))
     }
-    perspective <- attr(x, "perspective")
+
     package <- gsub("\\.", "\\\\.", package)
     if (exact) {
         str <- paste(package, collapse = "$(?!\\.)|^")
@@ -168,28 +179,34 @@ imports.cranly_network <- function(x, package = NULL, exact = FALSE) {
     else {
         str <- paste(package, collapse = "|")
     }
+
     inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
-    ## inds <- sapply(x$nodes$Package, function(x) any(grepl(str, x)))
+    ## inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
+
     out <- unique(unlist(x$nodes[inds, "imports"]))
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 }
 
 #' @rdname package_by
 #' @export
 depends.cranly_network <- function(x, package = NULL, exact = FALSE) {
+    if (attr(x, "perspective") == "author") {
+        stop(match.call()[[1]], " is not designed for cranly_network objects with perspective = 'author'")
+    }
+
     if (is.null(package)) {
         return(NULL) # return(unlist(x$nodes$Package))
     }
     if (any(is.infinite(package))) {
         return(unique(unlist(x$nodes$depends)))
     }
-    perspective <- attr(x, "perspective")
+
     package <- gsub("\\.", "\\\\.", package)
     if (exact) {
         str <- paste(package, collapse = "$(?!\\.)|^")
@@ -198,15 +215,17 @@ depends.cranly_network <- function(x, package = NULL, exact = FALSE) {
     else {
         str <- paste(package, collapse = "|")
     }
+
     inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
-    ## inds <- sapply(x$nodes$Package, function(x) any(grepl(str, x)))
+    ## inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
+
     out <- unique(unlist(x$nodes[inds, "depends"]))
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
     }
 }
 
@@ -214,13 +233,17 @@ depends.cranly_network <- function(x, package = NULL, exact = FALSE) {
 #' @rdname package_by
 #' @export
 linking_to.cranly_network <- function(x, package = NULL, exact = FALSE) {
+    if (attr(x, "perspective") == "author") {
+        stop(match.call()[[1]], " is not designed for cranly_network objects with perspective = 'author'")
+    }
+
     if (is.null(package)) {
         return(NULL) # return(unlist(x$nodes$Package))
     }
     if (any(is.infinite(package))) {
         return(unique(unlist(x$nodes$linkingto)))
     }
-    perspective <- attr(x, "perspective")
+
     package <- gsub("\\.", "\\\\.", package)
     if (exact) {
         str <- paste(package, collapse = "$(?!\\.)|^")
@@ -229,15 +252,53 @@ linking_to.cranly_network <- function(x, package = NULL, exact = FALSE) {
     else {
         str <- paste(package, collapse = "|")
     }
+
     inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
-    ## inds <- sapply(x$nodes$Package, function(x) any(grepl(str, x)))
+    ## inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
     out <- unique(unlist(x$nodes[inds, "linkingto"]))
 
     if (all(is.na(out)) | !length(out)) {
         return(NULL)
     }
     else {
-        return(out)
+        return(out[!is.na(out)])
+    }
+}
+
+
+#' @rdname package_by
+#' @export
+enhances.cranly_network <- function(x, package = NULL, exact = FALSE) {
+    if (attr(x, "perspective") == "author") {
+        stop(match.call()[[1]], " is not designed for cranly_network objects with perspective = 'author'")
+    }
+
+    if (is.null(package)) {
+        return(NULL) # return(unlist(x$nodes$Package))
+    }
+
+    if (any(is.infinite(package))) {
+        return(unique(unlist(x$nodes$enhances)))
+    }
+
+    package <- gsub("\\.", "\\\\.", package)
+    if (exact) {
+        str <- paste(package, collapse = "$(?!\\.)|^")
+        str <- paste0("^", str, "$(?!\\.)")
+    }
+    else {
+        str <- paste(package, collapse = "|")
+    }
+
+    inds <- grep(str, x$nodes$package, ignore.case = !exact, perl = TRUE)
+    ## inds <- sapply(x$nodes$package, function(z) any(grepl(str, z, ignore.case = !exact, perl = TRUE)))
+    out <- unique(unlist(x$nodes[inds, "enhances"]))
+
+    if (all(is.na(out)) | !length(out)) {
+        return(NULL)
+    }
+    else {
+        return(out[!is.na(out)])
     }
 }
 
diff --git a/man/as.igraph.cranly_network.Rd b/man/as.igraph.cranly_network.Rd
index cc28d7b..8ebed70 100644
--- a/man/as.igraph.cranly_network.Rd
+++ b/man/as.igraph.cranly_network.Rd
@@ -32,13 +32,13 @@ undirected network of authors.
 \examples{
 \dontrun{
 
-data("cran_sample", package = "cranly")
+#' cran_db <- clean_CRAN_db()
 ## Package directives network
-package_network <- build_network(object = cran_sample, perspective = "package")
+package_network <- build_network(object = cran_db, perspective = "package")
 igraph::as.igraph(package_network)
 
 ## Author collaboration network
-author_network <- build_network(object = cran_sample, perspective = "author")
+author_network <- build_network(object = cran_db, perspective = "author")
 igraph::as.igraph(author_network)
 
 }
diff --git a/man/cran_sample.Rd b/man/cran_sample.Rd
deleted file mode 100644
index fe225d9..0000000
--- a/man/cran_sample.Rd
+++ /dev/null
@@ -1,41 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/data.R
-\docType{data}
-\name{cran_sample}
-\alias{cran_sample}
-\title{Cleaned and processed CRAN package metadata from 30 March 2018}
-\format{An object of class \code{cranly_db} (inherits from \code{data.frame}) with 1000 rows and 64 columns.}
-\usage{
-cran_sample
-}
-\description{
-This is a random sample of 1000 R packages from a processed version
-of the result of a \code{\link[tools]{CRAN_package_db}()} call on
-30 March 2018. Specifically, the resulting data frame was passed to
-the \code{\link{clean_CRAN_db}} function and only the following
-variables have been kept:
-}
-\details{
-\itemize{
-  \item package
-  \item version
-  \item date
-  \item url
-  \item depends
-  \item imports
-  \item suggests
-  \item enhances
-  \item linkingto
-  \item license
-  \item author
-  \item maintainer
-  \item contact
-  \item md5sum
-}
-
-
-
-The author names have been converted to ASCII using transliteration
-through the \code{\link{iconv}} function.
-}
-\keyword{datasets}
diff --git a/man/package_by.Rd b/man/package_by.Rd
index 6bf1aaa..e14df6d 100644
--- a/man/package_by.Rd
+++ b/man/package_by.Rd
@@ -9,6 +9,7 @@
 \alias{imports}
 \alias{depends}
 \alias{linking_to}
+\alias{enhances}
 \alias{package_by.cranly_network}
 \alias{package_with.cranly_network}
 \alias{author_of.cranly_network}
@@ -17,6 +18,7 @@
 \alias{imports.cranly_network}
 \alias{depends.cranly_network}
 \alias{linking_to.cranly_network}
+\alias{enhances.cranly_network}
 \title{Find packages and authors by authors or packages with names matching a specific string}
 \usage{
 package_by(x, author = NULL, exact = FALSE)
@@ -35,6 +37,8 @@ depends(x, package = NULL, exact = FALSE)
 
 linking_to(x, package = NULL, exact = FALSE)
 
+enhances(x, package = NULL, exact = FALSE)
+
 \method{package_by}{cranly_network}(x, author = NULL, exact = FALSE)
 
 \method{package_with}{cranly_network}(x, name = NULL, exact = FALSE)
@@ -50,6 +54,8 @@ linking_to(x, package = NULL, exact = FALSE)
 \method{depends}{cranly_network}(x, package = NULL, exact = FALSE)
 
 \method{linking_to}{cranly_network}(x, package = NULL, exact = FALSE)
+
+\method{enhances}{cranly_network}(x, package = NULL, exact = FALSE)
 }
 \arguments{
 \item{x}{a \code{\link{cranly_network}} object}
@@ -67,9 +73,9 @@ Find packages and authors by authors or packages with names matching a specific
 }
 \examples{
 \dontrun{
-data("cran_sample", package = "cranly")
+cran_db <- clean_CRAN_db()
 ## Using a package directives network
-package_network <- build_network(cran_sample)
+package_network <- build_network(cran_db)
 ## Find all packages containing glm in their name
 package_with(package_network, name = "glm")
 ## Find all authors of packages containing brglm in their name
@@ -88,7 +94,7 @@ imports(package_network, package = "Rcpp", exact = TRUE)
 linking_to(package_network, package = "RcppArmadillo", exact = TRUE)
 
 ## Using an author collaboration network
-author_network <- build_network(cran_sample, perspective = "author")
+author_network <- build_network(cran_db, perspective = "author")
 ## Find all packages containing glm in their name
 package_with(author_network, name = "glm")
 ## Find all authors of packages containing brglm in their name
diff --git a/man/plot.cranly_network.Rd b/man/plot.cranly_network.Rd
index 359ddc3..45abae8 100644
--- a/man/plot.cranly_network.Rd
+++ b/man/plot.cranly_network.Rd
@@ -53,15 +53,15 @@ Interactive visualization of a package or author \code{\link{cranly_network}}
 }
 \examples{
 \dontrun{
-data("cran_sample", package = "cranly")
-package_network <- build_network(cran_sample)
+cran_db <- clean_CRAN_db()
+package_network <- build_network(cran_db)
 ## The package directives network of all users with Ioannis in
-## their name from the CRAN database subset cran_sample
+## their name from the CRAN database subset cran_db
 plot(package_network, author = "Ioannis")
 ## The package directives network of "Achim Zeileis"
 plot(package_network, author = "Achim Zeileis")
 
-author_network <- build_network(cran_sample, perspective = "author")
+author_network <- build_network(cran_db, perspective = "author")
 plot(author_network, author = "Ioannis", title = TRUE)
 }
 }
diff --git a/man/plot.summary_cranly_network.Rd b/man/plot.summary_cranly_network.Rd
index 799084c..9a5aa44 100644
--- a/man/plot.summary_cranly_network.Rd
+++ b/man/plot.summary_cranly_network.Rd
@@ -24,16 +24,16 @@ Top-n package or author barplots according to a range of network statistics
 \examples{
 
 \dontrun{
-data("cran_sample", package = "cranly")
+cran_db <- clean_CRAN_db()
 ## package network
-package_network <- build_network(cran_sample)
+package_network <- build_network(cran_db)
 package_summaries <- summary(package_network)
 plot(package_summaries, according_to = "n_imported_by", top = 30)
 plot(package_summaries, according_to = "n_depended_by", top = 30)
 plot(package_summaries, according_to = "page_rank", top = 30)
 
 ## author network
-author_network <- build_network(cran_sample, perspective = "author")
+author_network <- build_network(cran_db, perspective = "author")
 author_summaries <- summary(author_network)
 plot(author_summaries, according_to = "n_collaborators", top = 30)
 plot(author_summaries, according_to = "n_packages", top = 30)
diff --git a/tests/testthat/test-extractors.R b/tests/testthat/test-extractors.R
index 2c08e8c..f3a3467 100644
--- a/tests/testthat/test-extractors.R
+++ b/tests/testthat/test-extractors.R
@@ -5,16 +5,16 @@ package_network <- build_network(object = cran_db)
 author_network <- build_network(object = cran_db, perspective = "author")
 
 test_that("author_of returnes same value when applied to a package network and when applied to an author network",
-          expect_equal(sort(author_of(package_network, "MASS")),
-                       sort(author_of(author_network, "MASS")))
+          expect_equal(sort(author_of(package_network, "MASS", exact = TRUE)),
+                       sort(author_of(author_network, "MASS", exact = TRUE)))
 )
 
 test_that("package_by with exact = TRUE returns correct results", {
           expect_true(all(package_by(package_network, "Ioannis Kosmidis", exact = TRUE) %in%
-                       c("betareg", "brglm", "brglm2", "enrichwith", "PlackettLuce",
+                       c("betareg", "brglm", "brglm2", "cranly", "enrichwith", "PlackettLuce",
                          "profileModel", "trackeR")))
           expect_true(all(package_by(author_network, "Ioannis Kosmidis", exact = TRUE) %in%
-                       c("betareg", "brglm", "brglm2", "enrichwith", "PlackettLuce",
+                       c("betareg", "brglm", "brglm2", "cranly", "enrichwith", "PlackettLuce",
                          "profileModel", "trackeR")))
 }
 )
@@ -24,3 +24,11 @@ test_that("author_of with exact = TRUE returns correct results", {
 }
 )
 
+test_that("suggets, imports, linking_to works", {
+    expect_true(all(suggests(package_network, "cranly", exact = TRUE) == c("testthat", "knitr", "rmarkdown", "covr")))
+    expect_equal(imports(package_network, "cranly", exact = TRUE),
+                 c("visNetwork", "colorspace", "igraph", "magrittr", "stringr",
+                   "ggplot2", "countrycode"))
+    expect_equal(linking_to(package_network, "RcppArmadillo", exact = TRUE),
+                 "Rcpp")
+})